A urea cycle disorder (UCD) is an inborn error of metabolism caused by a deficiency of one of the enzymes in the urea cycle, which is responsible for removing ammonia from the blood and brain. The toxic ammonia can accumulate causing coma and brain damage. UCDs are associated with high morbidity and mortality rates. Surviving newborns with severe defects suffer developmental disability and are at increased risk for fatal crises. Chronic and acute episodes of hyperammonemia in children with partial defects result in cognitive and neurological deficits. There is currently no cure, although novel therapies have improved the outcome for many affected individuals. This R13 conference grant application requests funding to help support a Urea Cycle Disorder Satellite Symposium to the 12th International Congress of Inborn Errors of Metabolism (ICIEM) Conference in Barcelona, Spain on September 2, 2013. The ICIEM Conference, to take place September 3-7, 2013, will draw UCD experts from around the world. In order to take advantage of this opportunity, the Urea Cycle Disorders Consortium (UCDC) will organize a scientific symposium, titled International Symposium on Urea Cycle Disorders (UCD): Catalyzing New Therapeutic Approaches, in conjunction with the European Registry and Network for Intoxication Type Metabolic Diseases (E-IMD), and the National Urea Cycle Disorders Foundation (NUCDF) patient advocacy group. UCD Satellite Symposia to the ICIEM Conference were held in Vienna in 1997, Sydney in 2003, and La Jolla in 2009. Proceedings from these symposia were published in the Journal for Inherited Metabolic Disease and Molecular Genetics and Metabolism. Interest and participation have increased with each of these meetings with more than 200 participants involved in 2009. We expect 250-300 participants in 2013. NIH support will help us continue this tradition, bringing together UCD experts from around the world to share research discoveries and encourage and accelerate collaborative research. Trainees will be encouraged to attend the conference to supplement their training and to submit abstracts to compete for travel awards. The proposed conference format is a full day program divided into four sessions: 1) pathophysiological insights suggesting novel therapeutic approaches, 2) early detection and new treatment principles, 3) longitudinal studies across the world with focus on differences, and 4) clinical themes and patient outcomes. There will also be poster presentations, giving trainees a chance to share with each other and with senior investigators and receive feedback. The symposium will be preceded by a joint UCDC/E-IMD meeting on Sept. 1 and a welcome reception that evening, giving additional time to review posters, network, and establish relationships. There will be an evaluation of the symposium; participants will fill out a form indicating the level of success in achieving our goals Finally, the proceedings will be published by Molecular Genetics and Metabolism.